Automatic line shut-off



J. A. coY,

AUTOMATIC LINE SHUT-OFF Dec. 31, 1940.

Filed Jan.

Jam/7 ,4. 60y

INVENTOR 'ufl ATTORNEY Patented Dec. 31, 1940' UNITED STATES PATENTOFFICE 3 Claims.

The invention relates to a pressure controlled automatic line cutoff,and has for its object to provide a device of this character whereby apredetermined pressure flow is allowed to pass through the line undernormal conditions, and the device closed upon loss of pressure on thedown stream side thereof, upon breakage of the line between the controldevice'and the point of delivery.

A further object is to provide an automatic.

cutoff, pressure controlled, and particularly adapted to be positionedin a line leading from a Christmas tree of an oil well, and discharginginto a separator or gasoline plant, and so constructed that it ismaintained open by pressure from the line on the upstream side-thereofand provided with-means whereby it will close and,

stop the flow upon lossof pressure on the down stream side of thedevice.

A further object is to provide the device with a cylinder having apiston slidably mounted therein and controlling a valve cooperating witha valve seat in the line, a feed line from the up stream side anddischarging into the cylinder above and below the piston for equalizingthe pressure on the opposite sides of the piston and allowing anadjustable spring to overbalance the pressure within the cylinder andmaintain the valve open. Also to provide a feed line from the upper endof the cylinder to the down stream side of the line, which whenopened'allows pressure from the down stream side of the line to enterthe cylinder above the piston upon closing of the first mentioned teedline to the upper end of the cylinder. The downstream feed line formsmeans whereby the valve will be closed upon loss of pressure on the downstream side of the device in case of breakage. l

A further object is to the tension of the spring can be varied forvarying the pressure difierential between the upstream and down-streamsides of'the device.

with the above and other objects in view the invention resides in thecombination and arrangement of parts as hereinafter set forth, shown inthe drawing, described and claimed, it being understood that changes inthe precise embodiment of the invention may be made within the scope ofwhat is claimed without departing from the spirit .oi'the invention.

@1121 the drawing: 7

Figure 1 is a vertical longitudinal sectional view throughthe automaticline cut oil.

Figure 2 is a side elevation ot the device show,

ing the same applied to a line leading from a provide means whereby-Christmas tree of an 'oil well to a separator or gasoline tank, which isusually remotely located in relation to the oil well.

Referring to the drawing, the numera l l designates a conventional formof Christmas tree arsed in connection with oilwells for connectingvarious pipe lines, and 2 one of said pipe lines which. leads to aseparator or gasoline plant 3, remotely located in relation to the well.The automatic cut oif device hereinafter described is preferablypositioned adjacent the well, and the control valves 4 carried by theChristmas tree, hence there is no necessity for an automatic control ofthe device upon breakage of the line between the device and the well, asit will only be necessary for the operator to cut oil! the flow byclosing the valves 4 onthe Christmas tree, however the automatic out 011is particularlydesigned to operate upon loss oi. pressure on the downstream side thereof where there is a long flight 01. pipe to the 'pointof discharge and upon breakage of said Pipe.

The discharge line 2 is provided with an orifice choke 5 on the upstreamside of the device, and which choke is held in place by means of a union6. The automatic cut 011 comprises a body 1 having a port 8 extendingtherethroughand a valve seat 9 with which the disc valve lll cooperatesfor cutting oil the flow through the line. Disc valve lllis providedwith a rod II which 5 extends upwardly through the valve seat and isslidably mounted in a packing gland l2. Secured to the upper side of thevalve casing I is 9, cylinder I3, in whichis slidably mounted a pistonll, carried by the upper end 01' the connecting rod ll. Interposedbetween the upper side 01' the piston H anda disc I5 is an expansionspring IS, the purpose of which will presently appear. The expansivepower of the spring l6 may be adjusted or varied by means of theadjusting screw 11 carried by the head I8 0! the cylinder l3.

7 Connected into the line 2 on the well side or the choke 5 is a feedline l9, whichterminates in I branches 20 and 2|, and discharge into thecylinder l3 above and below the piston l4. Branches -20 and 2| areprovided with valves A and B-tor controlling the now therethrough. Y Itwill be, noted that when the valves A and B are opened and valve. Cclosed that the pressure from the V upstream side will enter thecylinder above and below the piston I4, and this pressure will; be equalon both sides of the piston. As the spring I6 exerts a downward pressureonothe piston, .thevalve lu willbe aintained open. when the pressure inthe line b up, the valve Ais closed.

and the valve C opened, thereby allowing the: pressure from thedown-stream side to pass: through the feed line 22 into the upper end ofthe cylinder above the piston l4 and maintain the valve I!) open. Uponbreakage of the line on the down stream side there is a loss of pressurefrom the upper end of the cylinder above the piston pounds.

through the line 22 and the pressure through the valve C, and bothvalves A and B are opened.

When the pressure builds up and equalizes above and below the piston It,the additional spring pressure above the piston will cause the discvalve it) to be moved to open position, after which the valve A isclosed, and the valve C opened for allowing the pressure from the downstream side, in combination with the spring action, to maintain the discvalve open for the further operation of the device.

As anexample of operation, assuming the well pressure is threethousand-pounds, and the down stream pressure has a differential ofninety-nine pounds, while the spring pressure is one hundred It will beseen there are three thousandl pounds pushing upwardly on the under sideof the piston from the high side through the feedthousand and onepounds. downward pressure,

which will hold the unit open along with the weight of the piston l4,its connecting rod II and disc valve III. So long as this diflerentialisv maintained, the units will remain open, but should a break occur onthe down-stream side which would disturb the ratio of difierential theresistance on top of the piston would become weakened, and the pressureunderneath the piston,

from the feed line 19, would overcome the lowered pressure above thepiston together with the spring action, and the piston would be forcedupwardly V and the-valve Ill closed against the seat 9.

After the break is repaired there would be no pressure in the line belowthe unit. To again open the unit for use it would be necessary to shutthe valve 4 on the Christmas tree and open the valve A,,and after ashort while the pressure all through the unit, down to the deliverypoint, would become equal, at which time the unit would open by force ofthe spring only, as all other presfull" and the normal difierentialpressures exist throughout the system.

During the above period the high pressure above and below the pistonhave held the valve open. The next operation is to close the valve A andopen the valve C, so the device will again automatically operate in-caseof a break. The valve C is provided primarily so the upper part of thecylinder will not be bled of pressure from the feed line 20 when thevalve A is open, during the initial operation. Valve A is manipulatedfor the mechanical setting of the device, so the valve [0 will beopened. After the valve A is closed, the valve C is opened, so thedevice will automatically operate by loss of pressure on the down-streamside for closing ofi the flow.

The invention having been set forth, what is I claimed as new and usefulis:

1. The combination with a pressure pipe line, and a pressure reductionchoke in said line, of an automatic cut cit device therefor on the downstream side of said choke, said device comprising a valve cooperatingwith a valve seat in the line between the high' pressure side of theline and the lower pressure side on the down stream side of the choke, apressure cylinder, a rod carried by the valve and extending into thepressure cylinder, a piston within the pressure cylinder, a feed lineconnecting the high pressure side of the pressure line on the up streamside of the choke with the cylinder above and below the piston andforming means for equalizing the pressure on both sides of the piston,an expansion spring within the cylinder above the piston and normallyurging the piston downwardly and the valve to open positionfa downstream feed line connecting the low pressure side with the cylinderabove the piston and forming means for bleeding the cylinder above thepiston upon a down stream breakage of the pressure line thereby allowingthe up-stream feed line pressure beneath the piston to' close the valve.

2. A device as set forth in claim 1 wherein the high'pressure feed lineterminates in branches connected to the cylinder above and below thepiston, valves carried by said branches, a valve carried by the downstream feed line and adapted to be closed when both of the valves of theupstream feed line are open and to be opened whenthe up-stream feed linevalve discharging into the cylinder above the piston is closed, therebyallowing the valve to be maintained open by the down stream pressuredifferential and the spring.

3. A device as set forth in claim 1 including valve means for cuttingoff the pressure from the upper end of the cylinder in the up-streamfeed line and valve means in the down-stream feed ,line for preventingbleeding of the upper end of the cylinder during the pressure equalizingoperation and when opened forming means for bleeding the upper end ofthe cylinder upon loss of pressure on the down "ream side of the cutoil.

JOSEPH A. COY.

